Java converting image to ascii as String

Question

I am trying to write an application which takes an image, get red/green/blue values of each pixels, get the average value (converting into grayscale), change colors to ASCII values. The problem is that I am getting an error:

java.lang.ArrayIndexOutOfBoundsException: Coordinate out of bounds!

I know what does it mean, but I cant locate it in my code. Bellow my code:

public void convert(File path) {

        StringBuilder sb = new StringBuilder();

        int[][] red = null;
        int[][] green = null;
        int[][] blue = null;
        int[][] avg = null;

        try {
            BufferedImage img = ImageIO.read(path);

            red = new int[img.getHeight()][img.getWidth()];
            green = new int[img.getHeight()][img.getWidth()];
            blue = new int[img.getHeight()][img.getWidth()];
            avg = new int[img.getHeight()][img.getWidth()];

            for (int i = 0; i < img.getHeight(); i++) {
                for (int j = 0; j < img.getWidth(); j++) {

                    int pixel = img.getRGB(i, j);
                    Color c = new Color(pixel, true);

                    red[i][j] = c.getRed();
                    green[i][j] = c.getGreen();
                    blue[i][j] = c.getBlue();

                    avg[i][j] = red[i][j] / 3 + green[i][j] / 3 + blue[i][j] / 3;

                    // ".:-=+*#%@"

                    if (avg[i][j] <= 25) {
                        sb.append("'");
                    } else if (avg[i][j] <= 50) {
                        sb.append(".");
                    } else if (avg[i][j] <= 75) {
                        sb.append(":");
                    } else if (avg[i][j] <= 100) {
                        sb.append("-");
                    } else if (avg[i][j] <= 125) {
                        sb.append("=");
                    } else if (avg[i][j] <= 150) {
                        sb.append("+");
                    } else if (avg[i][j] <= 175) {
                        sb.append("*");
                    } else if (avg[i][j] <= 200) {
                        sb.append("#");
                    } else if (avg[i][j] <= 225) {
                        sb.append("%");
                    } else if (avg[i][j] <= 255) {
                        sb.append("@");
                    }
                }
                sb.append("\n");
            }

        } catch (Exception e) {
            System.out.println(e);
        }

        System.out.println(sb.toString());

    }

First off -- get rid of `catch (Exception e)`. You should never catch all exceptions indiscriminately. Next isolate the error, find out which line is throwing the exception. — Hovercraft Full Of Eels, Oct 15 '16 at 15:47
This looks suspect: `<= 255`, but I can't say for sure. You're using lots of "magic" numbers, and that is risky. — Hovercraft Full Of Eels, Oct 15 '16 at 15:47
What do you mean by magic numbers? The max value of R/G/B is 255. — DEADALICE7000, Oct 15 '16 at 15:58
By magic numbers, I mean using numbers in place of constants and variables. This makes code much harder to debug. Again, make your exception catch block much more specific and always print out the full stack trace. Also note that your ave looks to always be 0 as you're doing int division. — Hovercraft Full Of Eels, Oct 15 '16 at 16:11
Sorry but I can't fully understand. I dont get it why my avg will be 0. — DEADALICE7000, Oct 15 '16 at 16:24
Sorry, I'm wrong, it won't be 0, but it's reliability would be improved by adding all the ints together and then dividing by 3. — Hovercraft Full Of Eels, Oct 15 '16 at 17:09
Your img.getRGB(i, j) should be img.getRGB(j, i). The getRGB method parameters are width and height. — Gilbert Le Blanc, Oct 15 '16 at 18:52
Fixed it. I'v replaced all getHeight with getWidth and vice versa. Now it is working but... the whole photo is turdned 270degree right site. I could just transform it again but I want to find a reason why it happens. — DEADALICE7000, Oct 15 '16 at 18:52
Your ASCII characters are backwards. Zero is black, and 255 is white. — Gilbert Le Blanc, Oct 15 '16 at 19:08
Changed it aswell, just didnt told you about this. Anyway thanks for help, have a nice night. — DEADALICE7000, Oct 15 '16 at 21:23

Java converting image to ascii as String

0 Answers0